Inertial sensors and inertial measuring devices

Abstract

To provide an inertial sensor that can suppress a decrease in reliability and a deterioration in yield. [Solution] The inertial sensor 1 comprises a base body 2, a lid 3 that forms a cavity S as a space between itself and the base body 2, a functional element 4 which is a capacitive element made of a semiconductor layer 23 and is placed in the cavity S, an adhesive layer 6 which is provided in the peripheral region P surrounding the cavity S and adheres the base body 2 and the lid 3 together, and a sealing portion 8 which is provided in the peripheral region P and seals the hole 7 between the cavity S and the outside. The sealing portion 8 is provided in contact with the lid 3 and the base body 2 and includes the material of the lid 3 and the material of the adhesive layer 6.

Description

Technical Field

[0006] , , , ,

[0001] The present invention relates to an inertial sensor, a method for manufacturing the inertial sensor, and an inertial measurement device including the inertial sensor.

Background Art

[0002]

[0003] As a method for sealing a package of MEMS (Micro Electro Mechanical Systems), there is one described in Patent Document 1. Patent Document 1 includes a MEMS wafer and a cap wafer, and by bonding the cap wafer to the MEMS wafer, a cavity for housing a sensor is formed. Then, by irradiating a laser beam, a hole leading to the cavity is opened in the cap wafer, and after adjusting the air pressure in the cavity, the cap wafer around the hole is melted by irradiating the hole in the cap wafer with a laser beam to close the hole.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Since the hole leading to the cavity is disposed on the sensor, there is a risk that the sensor in the cavity may be contaminated by splashes generated from the cap wafer due to irradiation with a laser beam, causing a decrease in reliability and a deterioration in yield.

Means for Solving the Problems

[0006] An inertial sensor according to one aspect of the present application comprises a substrate, a lid forming a space between itself and the substrate, a capacitive element made of a semiconductor layer disposed in the space, an adhesive layer provided in a peripheral region surrounding the space and bonding the substrate and the lid, and a sealing portion provided in the peripheral region and sealing a hole between the space and the outside, wherein the sealing portion is provided in contact with the lid and the substrate and includes the material of the lid and the material of the adhesive layer.

[0007] An inertial measuring device according to one aspect of the present invention comprises the inertial sensor described above and a control circuit for controlling the drive of the inertial sensor.

[0008] A method for manufacturing an inertial sensor according to one aspect of the present invention is a method for manufacturing an inertial sensor comprising a substrate, a lid that forms a space between itself and the substrate, and a capacitive element made of a semiconductor layer disposed in the space, the method comprising: forming a groove on a first surface of the lid that connects the space and the outside; bonding the first surface of the lid to the substrate via an adhesive layer to connect the space and the outside and form a hole consisting of the groove and the substrate; and irradiating the hole with laser light from a second surface of the lid opposite to the first surface, thereby forming a sealing portion that seals the hole with the molten material of the lid.

[0009] A method for manufacturing an inertial sensor according to one aspect of the present invention is a method for manufacturing an inertial sensor comprising a substrate, a lid that forms a space between itself and the substrate, and a capacitive element made of a semiconductor layer disposed in the space, the method comprising: forming a groove on a third surface of the substrate that connects the space to the outside; bonding the lid to the third surface of the substrate via an adhesive layer to connect the space to the outside and form a hole consisting of the groove and the lid; and irradiating the hole with laser light from the lid side to form a sealing portion that seals the hole with the molten material of the lid. [Brief explanation of the drawing]

[0010] [Figure 1] A perspective view of an inertial sensor according to Embodiment 1. [Figure 2] Cross-sectional view taken along line A-A of FIG. 1. [Figure 3] Cross-sectional view taken along line B-B of FIG. 1. [Figure 4] Plan view of the functional element. [Figure 5] Flowchart for explaining the manufacturing method of the inertial sensor. [Figure 6A] Diagram for explaining the manufacturing process. [Figure 6B] Cross-sectional view taken along line D-D of FIG. 6A. [Figure 7A] Diagram for explaining the manufacturing process. [Figure 7B] Diagram for explaining the manufacturing process. [Figure 8A] Diagram for explaining the manufacturing process of Embodiment 2. [Figure 8B] Cross-sectional view taken along line E-E of FIG. 8A. [Figure 9A] Diagram for explaining the manufacturing process. [Figure 9B] Diagram for explaining the manufacturing process. [Figure 10A] Explanatory drawing corresponding to the manufacturing process of Embodiment 3. [Figure 10B] Diagram for explaining the manufacturing process. [Figure 10C] Diagram for explaining the manufacturing process. [Figure 11] Exploded view of the inertial measurement device of Embodiment 4. [Figure 12] Perspective view of the substrate on which the inertial sensor used in the inertial measurement device of FIG. 11 is mounted.

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, in each of the following figures, in order to make each member recognizable, the scale of each member is made different from the actual one. In each figure, the X-axis, Y-axis, and Z-axis are shown as three mutually orthogonal axes. For convenience of explanation, the end point side of the arrow indicating the Z-axis is also referred to as "up", and the starting point side is also referred to as "down". Further, hereinafter, the direction parallel to the X-axis is also referred to as the "X-axis direction", the direction parallel to the Y-axis is also referred to as the "Y-axis direction", and the direction parallel to the Z-axis is also referred to as the "Z-axis direction". Also, the plane including the X-axis and the Y-axis is also referred to as the "XY plane", and viewing the XY plane in the Z-axis direction is also referred to as "planar view" or "planar". Also, viewing a cross-section including the Z-axis from a direction perpendicular to the cross-section is also referred to as "cross-sectional view" or "cross-sectional".

[0012] Furthermore, in the following description, for example, with respect to the substrate, the description "on the substrate" represents any of the cases where it is arranged in contact with the upper surface of the substrate, where it is arranged via other structures on the upper surface of the substrate, or where a part is arranged in contact with the upper surface of the substrate and a part is arranged via other structures.

[0013] 1. Embodiment 1 1.1. Overview of the inertial sensor FIG. 1 is an overall perspective view of the inertial sensor according to the present embodiment. The inertial sensor 1 can be used as an angular velocity sensor capable of measuring the angular velocity around the Z-axis (vertical axis). Such an inertial sensor 1 is composed of a package 10 in which a base body 2 and a lid body 3 are bonded via an adhesive layer 6 in their peripheral region P. The package 10 has a cavity S as a space in a region surrounded by the peripheral region P between the base body 2 and the lid body 3. The cavity S includes a functional element 4 as a capacitance element formed in the semiconductor layer 23. An external connection terminal 5 electrically connected to the functional element 4 is arranged at the projecting portion H of the base body 2 projecting from the lid body 3.

[0014] The base body 2 includes a base substrate 21 as a substrate, an embedded insulating layer 22 as a second insulating layer provided on the base substrate 21, a semiconductor layer 23 provided on the embedded insulating layer 22, and an insulating layer 24 as a first insulating layer provided on the semiconductor layer 23.

[0015] A processed portion 32, which is a recess, is provided on the upper surface 3b of the lid 3, which serves as the second surface. The processed portion 32 is used to seal the hole 7 that leads to the inside of the cavity S. By irradiating the processed portion 32 with laser light L, the hole 7 is sealed by the molten silicon of the lid 3. Therefore, the processing section 32 is provided in a position that overlaps with the hole 7 in a plan view. The processed portion 32 is located in the center of the long side of the peripheral region P, but is not limited to this. The processed portion 32 may be located anywhere in the peripheral region P, including corners, as long as it overlaps with the hole 7. However, as will be described later, a portion of the processed portion 32 is positioned to overlap with the adhesive layer 6 in a plan view, so that an alloy can be formed with the adhesive layer 6. The processed portion 32 may also be formed in an uneven shape with multiple recesses. Furthermore, the processed portion 32 may be a square, polygon, circle, etc., in a plan view.

[0016] Figure 2 is a cross-sectional view along line AA of Figure 1, and Figure 3 is a cross-sectional view along line BB of Figure 1. Both Figures 2 and 3 are cross-sectional views taken at the location of the processed section 32. As shown in Figure 2, the cavity S is formed in a cavity SOI (Silicon On Insulator) structure. The upper surface 21a of the base substrate 21 is provided with a recess 21b that opens toward the lid 3, and the lower surface 3a, which is the first surface of the lid 3, is provided with a recess 31 that opens toward the base substrate 21. The cavity S is formed from the recess 21b and the recess 31 by bonding the substrate 2 and the lid 3 together in the peripheral region P via an adhesive layer 6.

[0017] A semiconductor layer 23, provided on the embedded insulating layer 22, is equipped with a functional element 4, such as an acceleration sensor or an angular velocity sensor. The functional element 4 is positioned in the cavity S such that its function is not restricted. To this end, a first cavity S1, consisting of a recess 21b, is provided between the functional element 4 and the substrate 2, and a second cavity S2, consisting of a recess 31, is provided between the functional element 4 and the cover 3. In this embodiment, the embedded insulating layer 22 is provided on the recess 21b, but the embedded insulating layer 22b may be removed as appropriate during the manufacturing process. The insulating layer 24, which is placed on the semiconductor layer 23, has a laminated structure of insulating layer 24a and insulating layer 24b, with an external connection terminal 5 and a wiring layer 51 provided between insulating layer 24a and insulating layer 24b. In addition, a metal wiring layer (not shown) connecting the functional element 4 and the external connection terminal 5 is also provided between insulating layer 24a and insulating layer 24b.

[0018] A groove 33 is provided in the peripheral region P of the lid 3, connecting the inside and outside of the recess 31. When the base 2 and the lid 3 are bonded together with the adhesive layer 6, the groove 33 is formed by the adhesive layer 6 and the insulating layer 24b located on the lower side of the groove 33, i.e., the opening side of the groove 33, creating a hole 7 that connects the inside and outside of the cavity S.

[0019] As shown in Figure 3, the adhesive layer 6 consists of a first adhesive layer 6a provided on the base 2 side and a second adhesive layer 6b provided on the lid 3 side. By heating and pressing the first adhesive layer 6a and the second adhesive layer 6b using a thermocompression bonding method, the first adhesive layer 6a and the second adhesive layer 6b are bonded together, and the adhesive layer 6 is formed.

[0020] The outermost surface materials of the first adhesive layer 6a and the second adhesive layer 6b can be any material that forms a eutectic composition when heat-compressed. Preferably, the outermost surface of the first adhesive layer 6a can be aluminum (AL), and the outermost surface of the second adhesive layer 6b can be germanium (Ge). The first adhesive layer 6a and the second adhesive layer 6b may each be multilayer films, and may include, for example, a barrier layer made of titanium tungsten (TiW).

[0021] The hole 7 is provided to adjust the air pressure inside the cavity S. After adjusting the air pressure inside the cavity S, the hole 7 is sealed by the sealing part 8. This makes the cavity S airtight. When the functional element 4 is an angular velocity sensor element, it is preferable that the cavity S is in a vacuum state, for example, a reduced pressure state of 10 Pa or less, in order to efficiently vibrate the functional element 4. When the functional element 4 is an acceleration sensor element, it is preferable that the cavity S is in a state of near atmospheric pressure in order to allow the functional element 4 to exert a sufficient damping effect. The inside of the cavity S may also be replaced with an inert gas such as helium, argon, or nitrogen.

[0022] The sealing portion 8 is formed by melting the lid 3, which is made of a silicon substrate, by irradiation with laser light L. By irradiating the processing portion 32 from above the lid 3 with laser light L, the lid 3 between the processing portion 32 and the base body 2 melts, including the walls of the groove 33. The molten silicon fills the groove 33 and penetrates the adhesive layer 6, adhering tightly to the insulating layer 24b of the base body 2. In this way, the sealing portion 8 seals the hole 7. The sealing portion 8 is provided in contact with the lid 3 and the base body 2. That is, since the sealing portion 8 is provided in contact with the base body 2 without a cavity S in between, the scattering of molten silicon can be suppressed compared to the case where a cavity S is in between.

[0023] The sealing portion 8 has a first portion 8a as a first sealing portion that fills the groove 33 on the lid 3 side, and a second portion 8b as a second sealing portion that is in contact with the insulating layer 24b of the substrate 2. The first part 8a is a portion of the lid 3 that is mainly composed of silicon, which has been melted by irradiation with laser light L. Since the inner wall of the groove 33 is also melted by irradiation with laser light L, the interface between the first part 8a and the groove 33 is formed in a state where there is no interface, or where it is difficult to confirm the interface. Therefore, the structure of the first part 8a is highly effective in suppressing moisture from entering the cavity S from the outside by traveling across the interface.

[0024] Furthermore, the second portion 8b is made of an alloy of the silicon of the lid 3 and the metal of the adhesive layer 6. Because the second portion 8b is an alloy of silicon and the adhesive layer 6, it adheres well to the insulating layer 24b, which is made of silicon oxide, and voids are less likely to form at the interface with the insulating layer 24b. Therefore, there is a low possibility of a leak path being formed at the interface between the sealing portion 8 and the insulating layer 24b, and the intrusion of moisture into the cavity S can be suppressed for a long period of time.

[0025] In this way, the sealing portion 8 can suppress the intrusion of moisture into the cavity S over a long period of time, thereby suppressing the adhesion of the acceleration sensor and the decrease in the Q value of the angular velocity sensor caused by moisture intrusion, and providing an inertial sensor that can maintain reliability over a long period of time.

[0026] The base substrate 21 is formed from a glass material containing movable ions consisting of alkali metal ions, such as borosilicate glass like Pyrex® glass. This allows the functional element 4, formed from a silicon substrate, to be firmly bonded to the base substrate 21 by anodic bonding. However, the constituent material of the base substrate 21 is not limited to glass material; for example, a high-resistance silicon material can be used. In this case, bonding with the functional element 4 can be performed via, for example, a resin-based adhesive, glass paste, or a metal layer.

[0027] 1.2. Overview of Functional Elements Figure 4 is a plan view of the functional element. In Figure 4, the configuration of an angular velocity sensor element for detecting angular velocity around the Z axis is shown as the functional element. The functional element 4 includes a structure 41, a fixed electrode 47 for driving, and a fixed electrode 48 for detection.

[0028] Structure 41 has two vibrating bodies 41a and 41b, which are connected to each other along the X-axis. Furthermore, vibrating bodies 41a and 41b are provided symmetrically with respect to their respective boundary lines C. Since the configurations of vibrating bodies 41a and 41b are the same, the configuration of vibrating body 41a will be described as representative, and the description of the configuration of vibrating body 41b will be omitted below.

[0029] The vibrating body 41a includes a drive unit 42 and a detection unit 43. The drive unit 42 also includes a drive support unit 421, a drive spring unit 422, a drive movable electrode 423, and a fixed unit 424. The drive support portion 421 is frame-shaped and is connected via a drive spring portion 422 to a fixing portion 424 which is fixed to the upper surface 21a of the base substrate 21. The drive spring portion 422 is configured to be elastically deformable in the X-axis direction, thereby allowing the drive support portion 421 to vibrate in the X-axis direction relative to the fixed portion 424.

[0030] Furthermore, the drive movable electrode 423 is connected to the drive support portion 421 and is located outside the drive support portion 421. A drive fixed electrode 47 is positioned opposite the drive movable electrode 423, fixed to the upper surface 21a of the base substrate 21. Therefore, when a voltage is applied between the drive fixed electrode 47 and the drive movable electrode 423, an electrostatic force is generated between the drive fixed electrode 47 and the drive movable electrode 423. This electrostatic force causes the drive spring portion 422 to elastically deform while the drive support portion 421 can be vibrated along the X-axis direction.

[0031] The detection unit 43 is located inside the drive support unit 421 and includes a detection support unit 431, a detection spring unit 432, and a detection movable electrode 433. The detection support portion 431 is frame-shaped and is connected to the drive support portion 421 via the detection spring portion 432. The detection spring portion 432 is configured to be elastically deformable in the Y-axis direction, thereby allowing the detection support portion 431 to be displaced in the Y-axis direction relative to the drive support portion 421.

[0032] Furthermore, the detection movable electrode 433 is provided inside the detection support portion 431, extending in the X-axis direction, and both ends of it are connected to the detection support portion 431. The detection fixed electrode 48, fixed to the upper surface 21a of the base substrate 21, is positioned opposite the detection movable electrode 433 via the detection movable electrode 433. Therefore, when the detection support portion 431 vibrates in the Y-axis direction while the detection spring portion 432 is elastically deformed, the gap between the detection fixed electrode 48 and the detection movable electrode 433 changes, and the capacitance between the detection fixed electrode 48 and the detection movable electrode 433 changes in accordance with this change.

[0033] Functional element 4 with this configuration detects angular velocity around the Z-axis as follows: First, a voltage is applied between the fixed drive electrode 47 and the movable drive electrode 423 to vibrate the drive support portion 421 along the X-axis direction. At this time, the drive support portions 421 of the vibrating bodies 41a and 41b are vibrated in opposite phases to each other.

[0034] Thus, when an angular velocity ω around the Z axis is applied to the functional element 4 while the drive support portion 421 of the vibrating bodies 41a and 41b is vibrating, a Coriolis force acts, causing the detection support portion 431 of the vibrating bodies 41a and 41b to be displaced in the Y axis direction relative to the drive support portion 421. At this time, the detection support portions 431 of the vibrating bodies 41a and 41b are displaced in opposite phases to each other.

[0035] As the detection support portion 431 is displaced in the Y-axis direction relative to the drive support portion 421, the gap between the detection movable electrode 433 and the detection fixed electrode 48 changes, and in accordance with this gap change, the capacitance between the detection movable electrode 433 and the detection fixed electrode 48 changes.

[0036] Therefore, the functional element 4 applies a voltage between the detection movable electrode 433 and the detection fixed electrode 48 to detect the change in capacitance between them, and based on this change in capacitance, it can determine the angular velocity ω around the Z axis.

[0037] 1.3. Overview of the manufacturing method for inertial sensors Figure 5 is a flowchart illustrating the manufacturing method of an inertial sensor. Figures 6A, 6B, 7A, and 7B are diagrams illustrating each manufacturing step shown in the flowchart of Figure 5. Figure 6A is a perspective view showing the inertial sensor before the base 2 and lid 3 are bonded together, and Figure 6B is a cross-sectional view of Figure 6A along the DD line. Figure 7A is a cross-sectional view of the inertial sensor along the DD line after the base 2 and lid 3 have been bonded together, and Figure 7B is a cross-sectional view of the inertial sensor along the DD line showing the formation of the sealing portion 8 by irradiation with laser light L. As shown in Figure 6B, a first adhesive layer 6a is provided on the insulating layer 24b of the peripheral region P of the base body 2, and a second adhesive layer 6b is provided on the opposing lower surface 3a of the lid body 3. In addition, a wiring layer 51 is provided between the insulating layer 24a and the insulating layer 24b.

[0038] In the flowchart of Figure 5, in step S10, a groove 33 is formed on the lower surface 3a of the lid 3. As shown in Figure 6A, the groove 33 is provided to connect the inside and outside of the recess 31 provided in the lid 3. Note that the groove 33 is not limited to connecting the inside and outside of the recess 31 in a straight line. For example, there may be curved or bent parts in between.

[0039] In step S11, a recess is formed as the processed portion 32. As shown in Figure 6B, the processed portion 32 is provided on the upper surface 3b of the lid 3 at a position that overlaps with the groove 33 in a plan view. In this embodiment, the shape of the processed portion 32 is a pyramidal pyramid, but the shape of the processed portion 32 is not limited to this, and may be, for example, a frustum of a polygon, a frustum of a cone, or a cylindrical shape.

[0040] In step S12, the base body 2 and the lid body 3 are bonded together. As shown in Figure 7A, the base body 2 and the lid body 3 are bonded together by an adhesive layer 6. The adhesive layer 6 bonds the base body 2 and the lid body 3 by a eutectic layer formed by heat-pressing together the first adhesive layer 6a and the second adhesive layer 6b. By bonding the base body 2 and the lid body 3, a hole 7 is formed between the groove 33 and the base body 2, connecting the inside and outside of the cavity S. After adjusting the air pressure of the cavity S using the hole 7, the hole 7 is sealed by the sealing part 8.

[0041] In step S13, the sealing portion 8 is formed. As shown in Figure 7B, by irradiating the processing portion 32 provided in the peripheral region P of the lid 3 with laser light L, the silicon of the lid 3 between the processing portion 32 and the groove 33, and the silicon forming the inner wall of the groove 33 are melted. The melted silicon fills the groove 33 and penetrates the adhesive layer 6, adhering closely to the insulating layer 24b of the substrate 2, thereby forming the sealing portion 8. The sealing portion 8 is provided on the substrate 2 side of the lid 3. The sealing portion 8 is provided in contact with the lid 3 and the substrate 2. That is, since the sealing portion 8 is provided in contact with the substrate 2 without a cavity S in between, the scattering of molten silicon can be suppressed compared to the case where a cavity S is present.

[0042] In the sealing portion 8, the portion that fills the groove 33 is the first portion 8a, which serves as the first sealing portion. As described above, the first portion 8a is formed in such a way that there is no interface between the groove 33 and the first portion 8a, or in such a way that it is difficult to confirm the interface.

[0043] In the sealing portion 8, the portion that is in close contact with the insulating layer 24b is the second portion 8b, which serves as the second sealing portion. The second portion 8b is an alloy of molten silicon and the adhesive layer 6. The second portion 8b contains molten metal from the first adhesive layer 6a that overlaps with the groove 33 and the second adhesive layer 6b that is exposed on the inner wall of the groove 33. As a result, the lid 3 and the adhesive layer 6 are electrically conductive through the first portion 8a and the second portion 8b. This allows excess charge accumulated in the adhesive layer 6 to be released to the lid 3, preventing malfunctions.

[0044] Since the sealing portion 8 that seals the hole 7 is provided in the peripheral region P of the cavity S, even if the lid 3 is irradiated with laser light L to form the sealing portion 8, contamination of the functional element 4 by molten silicon can be suppressed.

[0045] As described above, the inertial sensor 1 of this embodiment provides the following effects. The inertial sensor 1 of this embodiment comprises a base body 2, a lid 3 that forms a cavity S as a space between itself and the base body 2, a functional element 4 which is a capacitive element made of a semiconductor layer 23 and is placed in the cavity S, an adhesive layer 6 which is provided in the peripheral region P surrounding the cavity S and adheres the base body 2 and the lid 3 together, and a sealing portion 8 which is provided in the peripheral region P and seals the hole 7 between the cavity S and the outside, wherein the sealing portion 8 is provided in contact with the lid 3 and the base body 2 and includes the material of the lid 3 and the material of the adhesive layer 6. With this configuration, since the sealing portion 8 that seals the hole 7 is provided in the peripheral region P of the cavity S, even if the hole 7 is sealed by the sealing portion 8 which includes the material of the lid 3, contamination of the functional element 4 placed in the cavity S can be suppressed. Furthermore, since the sealing portion 8 includes the material of the lid 3 and the material of the adhesive layer 6, it has excellent adhesion, and the generation of voids at the interface between the sealing portion 8 and the hole 7, as well as the formation of leak paths, can be suppressed. Therefore, when the inertial sensor of this embodiment is applied to an acceleration sensor, it is possible to suppress the sticking of the functional element 4 due to the intrusion of moisture, thereby providing a highly reliable acceleration sensor. Furthermore, when the inertial sensor of this embodiment is applied to an angular velocity sensor, it is possible to suppress the decrease in the Q value of the angular velocity sensor due to the intrusion of moisture or air, thereby providing an angular velocity sensor that can maintain reliability over a long period of time.

[0046] The inertial sensor 1 of this embodiment further comprises a base body 2 having a base substrate 21 as a substrate and an insulating layer 24 as a first insulating layer provided between the base substrate 21 and the cover 3, the hole 7 includes a groove 33 provided in the cover 3 and opening toward the base body 2, and the sealing portion 8 is in contact with the insulating layer 24. With this configuration, the hole 7 includes the groove 33 provided in the lid 3, and the sealing portion 8 fills the groove 33 and is in contact with the insulating layer 24, so that a good contact surface can be formed between the sealing portion 8 and the insulating layer 24.

[0047] In this embodiment, the inertial sensor 1 further includes a processed portion 32 having a recess in the lid 3, which overlaps with the sealing portion 8 in a plan view. With this configuration, the processing section 32 is provided in a shape with a recess, so the silicon of the lid 3 of the processing section 32 is more easily melted by irradiation with laser light L. Therefore, processing time can be shortened and processing quality can be improved. Furthermore, the recess 32 of the lid 3 is positioned to overlap with the adhesive layer 6 in a plan view. This facilitates the formation of an alloy between the sealing portion 8 and the adhesive layer 6. As a result, the sealing portion 8 can achieve good sealing performance.

[0048] The method for manufacturing the inertial sensor 1 of this embodiment comprises a base body 2, a lid 3 that forms a cavity S as a space between itself and the base body 2, and a functional element 4 as a capacitive element consisting of a semiconductor layer 23 disposed in the cavity S, and includes the steps of: S10 forming a groove 33 on the lower surface 3a of the lid 3 as the first surface, which communicates the cavity S with the outside; S12 bonding the lower surface 3a of the lid 3 to the base body 2 via an adhesive layer 6 to form a hole 7 that communicates the cavity S with the outside and consists of the groove 33 and the base body 2; and S13 irradiating the hole 7 with laser light L from the upper surface 3b of the lid 3 as the second surface opposite to the lower surface 3a, and forming a sealing portion 8 that seals the hole 7 with the molten material of the lid 3. With this configuration, by bonding the base body 2 and the lid body 3, a hole 7 is formed from the groove 33 provided in the lid body 3 and the base body 2. Since the hole 7 is sealed with the molten silicon of the lid body 3, a good adhesion surface can be formed between the molten silicon and the hole 7, thus suppressing the generation of voids at the interface between the sealing portion 8 and the hole 7, and preventing the formation of leak paths. Furthermore, by sealing the hole 7, contamination of the functional element 4 placed in the cavity S can be suppressed.

[0049] The manufacturing method of the inertial sensor 1 of this embodiment further includes a step S11 in which a processed portion 32 consisting of a recess is formed at a position overlapping with the groove 33 of the lid 3, and in a step S13 in which a sealing portion 8 is formed, a laser beam L is irradiated onto the processed portion 32 to form a first portion 8a as a first sealing portion made of the material of the lid 3 and a second portion 8b as a second sealing portion made of the material of the lid 3 and the material of the adhesive layer 6. With this configuration, the processing area 32 to which the laser beam L is irradiated has a shape with a recess, which makes it easier for the silicon of the lid 3 to melt when irradiated with the laser beam L. Therefore, it is possible to shorten the processing time and improve the processing quality.

[0050] 2. Embodiment 2 Embodiment 2 describes an inertial sensor 101 according to another embodiment of the inertial sensor 1 according to Embodiment 1. In the following description, the same reference numerals are used for the same components and processes as in Embodiment 1, and redundant explanations are omitted. Figures 8A, 8B, 9A, and 9B illustrate the manufacturing process of the inertial sensor according to Embodiment 2. Figure 8A is a perspective view showing the inertial sensor 101 before the base 102 and lid 103 are bonded together, and Figure 8B is a cross-sectional view of Figure 8A along the EE line. Figure 9A is a cross-sectional view of the inertial sensor 101 along the EE line when the base 2 and lid 3 are bonded together, and Figure 9B is a cross-sectional view of the inertial sensor 101 along the EE line showing the formation of the sealing portion 108 by irradiation with laser light L.

[0051] As shown in Figures 8A and 8B, the inertial sensor 101 according to Embodiment 2 has a groove 133 provided on the upper surface 102a, which is the third surface of the base body 102. The groove 133 is provided in the insulating layer 124 of the base body 102, exposing the insulating layers 124a and 124b on the inner wall and the semiconductor layer 123 at the bottom of the groove 133. The groove 133 is provided so as to traverse the peripheral region P and communicates the inside and outside of the cavity S. Furthermore, the processed portion 132, which consists of a recess, is provided in the surrounding region P at a position that overlaps with the groove 133 in a plan view. In this embodiment, the processed portion 132 is provided in the shape of a frustocone or cylinder. In addition, a part of the processed portion 132 is positioned at a position that overlaps with the adhesive layer 106 in a plan view.

[0052] As shown in Figure 9A, the substrate 102 and the lid 103 are thermocompressed together in the same manner as in Embodiment 1 to form an adhesive layer 106 with a first adhesive layer 106a and a second adhesive layer 106b. In this embodiment, the outermost surface of the first adhesive layer 106a on the substrate 102 side is germanium Ge, and the outermost surface of the second adhesive layer 106b on the lid 3 side is germanium Ge. If a polysilicon layer is used for the wiring layer on the substrate 102 side, the conductive layer of the substrate 102 will consist only of silicon, thus enabling the formation of a clean element. By bonding the base 102 and the lid 103 together, a hole 7 is formed by the groove 133 and the lid 103.

[0053] As shown in Figure 9B, the processed portion 132 is irradiated with laser light L to form the sealing portion 108. By irradiating the processed portion 132 with laser light L from above the lid 103, the silicon of the lid 103 between the processed portion 132 and the groove 133 is melted. The melted silicon penetrates the adhesive layer 106, fills the groove 133, and reaches the semiconductor layer 123, thereby forming the sealing portion 108. The sealing portion 108 is provided in contact with the substrate 102 and the lid 103. That is, since the sealing portion 108 is provided in contact with the substrate 102 without a cavity S in between, the scattering of molten silicon can be suppressed compared to the case where a cavity S is in between.

[0054] The sealing portion 108 has a first portion 108a, a second portion 108b, a third portion 108c, and a fourth portion 108d. The first part 108a is the portion on the lid 3 side that was melted by irradiation with laser light L. The second part 108b is a portion made of an alloy formed by molten silicon and the adhesive layer 106 when it penetrates the adhesive layer 106.

[0055] The third portion 108c is the part that fills the groove 133 provided in the insulating layer 124. Since the insulating layers 124a and 124b exposed on the inner wall of the groove 133 are both formed from a silicon oxide film, they have good compatibility with the third portion 108c, which is mainly composed of molten silicon. Therefore, the third portion 108c is formed in a state where there is no interface between the molten silicon and the insulating layer 124, or in a state where it is difficult to confirm the interface.

[0056] The fourth portion 108d is the part where molten silicon from the lid 103 reaches the semiconductor layer 123, melts the surface of the semiconductor layer 123, and adheres closely to the semiconductor layer 123. Since the semiconductor layer 123 is also made of silicon, the fourth portion 108d is formed in a state where there is no interface between the molten silicon and the semiconductor layer 123, or in a state where it is difficult to confirm the interface. Therefore, the sealing portion 108 can also be configured in a way that is highly effective in suppressing moisture from entering the cavity S from the outside by traveling across the interface, similar to the first embodiment.

[0057] Furthermore, since the sealing portion 108 is in contact with the lid 103 and the semiconductor layer 123 via the first portion 108a to the fourth portion 108d, electrical conductivity can be established between the lid 103 and the semiconductor layer 123. This allows excess charge accumulated in the semiconductor layer 123 to be released to the lid 103, preventing malfunctions.

[0058] As described above, the inertial sensor 101 of this embodiment provides the following effects in addition to the effects of Embodiment 1. The inertial sensor 101 of this embodiment further comprises a base 102 which includes a base substrate 121 as a substrate, an insulating layer 124 as a first insulating layer provided between the base substrate 121 and the cover 103, and a semiconductor layer 123 provided between the base substrate 121 and the insulating layer 124. The hole 7 includes a groove 133 provided in the insulating layer 124 and opening toward the cover 103, and the sealing portion 108 is in contact with the semiconductor layer 123. With this configuration, the hole 7 includes a groove 133 provided in the insulating layer 124 of the substrate 102, and the sealing portion 108 fills the groove 133 and is in contact with the semiconductor layer 123, so that a good adhesion surface can be formed between the sealing portion 108 and the insulating layer 124 and the semiconductor layer 123.

[0059] In this embodiment, the inertial sensor 101 is further electrically connected to the cover 103 and the semiconductor layer 123 via a sealing portion 108. With this configuration, there is no need to provide separate wiring to connect the cover 103 and the semiconductor layer 123, thus reducing the number of components, processes, and costs, while also improving reliability.

[0060] The method for manufacturing the inertial sensor 101 of this embodiment comprises a base body 102, a lid 103 that forms a cavity S as a space between itself and the base body 102, and a functional element 4 as a capacitive element consisting of a semiconductor layer 123 disposed in the cavity S. The method for manufacturing the inertial sensor 101 comprises: step S10 of forming a groove 133 on the third surface 102a of the base body 102 that communicates the cavity S with the outside; step S12 of bonding the lid 103 to the upper surface 102a of the base body 102 via an adhesive layer 106 to communicate the cavity S with the outside and form a hole 7 consisting of the groove 133 and the lid; and step S12 of irradiating a laser beam L from the lid 103 side toward the hole 7 to form a sealing portion 108 that seals the hole 7 with the molten material of the lid 103. With this configuration, by bonding the base body 102 and the lid body 103, a hole 7 is formed from the groove 133 provided in the base body 102 and the lid body 103. Since the hole 7 is sealed with the molten silicon of the lid body 103, a good adhesion surface can be formed between the molten silicon and the hole 7, thereby suppressing the generation of voids at the interface between the sealing portion 108 and the hole 7, and preventing the formation of leak paths. Furthermore, by sealing the hole 7, contamination of the functional element 4 placed in the cavity S can be suppressed.

[0061] 3. Embodiment 3 Embodiment 3 will describe an inertial sensor 201 according to another embodiment. In the following description, the same reference numerals are used for the same components and processes as in Embodiment 1, and redundant explanations are omitted. Figures 10A, 10B, and 10C illustrate the manufacturing process of the inertial sensor according to Embodiment 3.

[0062] Figure 10A is a cross-sectional view of the inertial sensor 201 before the base body 202 and the lid body 203 are bonded together, Figure 10B is a cross-sectional view of the inertial sensor 201 after the base body 2 and the lid body 3 are bonded together, and Figure 10C is a cross-sectional view of the inertial sensor showing the formation of the sealing portion 208 by irradiation with laser light L. Note that Figures 10A, 10B, and 10C all show cross-sections cut at the position of the EE line in Figure 8A.

[0063] As shown in Figure 10A, the inertial sensor 201 according to Embodiment 3 has a groove 233 provided in the base body 202. The groove 233 is provided in the insulating layer 224, the semiconductor layer 223, and the embedded insulating layer 222, exposing the insulating layer 224, the semiconductor layer 223, and the embedded insulating layer 222 on the inner wall, and exposing the base substrate 221 at the bottom of the groove 233. The groove 233 is also provided so as to traverse the peripheral region P and communicates the inside and outside of the cavity S.

[0064] Furthermore, the processed portion 232 having a recess is provided in the peripheral region P at a position that overlaps with the groove 233 in a plan view. In this embodiment, the processed portion 232 is formed with an uneven shape having multiple recesses on its surface to facilitate melting by the laser light L. Also, a part of the processed portion 232 is positioned at a position that overlaps with the adhesive layer 206 in a plan view.

[0065] As shown in Figure 10B, the base body 202 and the lid body 203 are heat-pressed together in the same manner as in Embodiment 1 to form an adhesive layer 206 by the first adhesive layer 206a and the second adhesive layer 206b. In this embodiment, the outermost surfaces of the first adhesive layer 206a on the base body 202 side and the second adhesive layer 206b on the lid body 203 side are both made of gold (Au). By bonding the base 202 and the lid 203 together, a hole 7 is formed by the groove 233 and the lid 203.

[0066] As shown in Figure 10C, the processed portion 232 is irradiated with laser light L to form the sealing portion 208. By irradiating the processed portion 232 with laser light L from above the lid 203, the lid 203 between the processed portion 232 and the groove 233 is melted. The molten silicon from the lid 203 penetrates the adhesive layer 206, fills the groove 233, and reaches the semiconductor layer 223, thereby forming the sealing portion 208. The sealing portion 208 is provided in contact with the substrate 202 and the lid 203. That is, since the sealing portion 208 is provided in contact with the substrate 102 without a cavity S in between, the scattering of molten silicon can be suppressed compared to the case where a cavity S is in between.

[0067] The sealing portion 208 has a first portion 208a, a second portion 208b, a third portion 208c, a fourth portion 208d, a fifth portion 208e, and a sixth portion 208f. The first part 208a is the portion on the lid 203 side that was melted by irradiation with laser light L. The second part 208b is a portion made of an alloy formed by molten silicon and the adhesive layer 206 when it penetrates the adhesive layer 206. The third portion 208c is the portion that contacts the insulating layer 224 exposed on the inner wall of the groove 233. Similar to the third portion 108c of Embodiment 2, the third portion 208c is formed in a state where there is no interface between the molten silicon and the insulating layer 224, or in a state where it is difficult to confirm the interface.

[0068] The fourth portion 208d is the portion that is in contact with the semiconductor layer 223 exposed on the inner wall of the groove 233. Since the semiconductor layer 223 is also made of silicon, the fourth portion 208d is formed in a state where there is no interface between the molten silicon and the semiconductor layer 223, or in a state where it is difficult to confirm the interface.

[0069] The fifth portion 208e is the part that contacts the embedded insulating layer 222 exposed on the inner wall of the groove 233. Since the embedded insulating layer 222 exposed on the inner wall of the groove 233 is formed from a silicon oxide film, it has good compatibility with the fifth portion 208e, which is mainly composed of molten silicon. Therefore, the fifth portion 208e is formed in a state where there is no interface between the molten silicon and the embedded insulating layer 222, or in a state where it is difficult to confirm the interface.

[0070] The sixth portion 208f is the portion where the molten silicon reaches the base substrate 221, melts the surface of the base substrate 221, and adheres closely to the base substrate 221. Since the base substrate 221 is also made of silicon, the sixth portion 208f is formed in a state where there is no interface between the molten silicon and the base substrate 221, or in a state where it is difficult to confirm the interface. Therefore, the sealing portion 208 can also be configured in a way that is highly effective in suppressing moisture from entering the cavity S from the outside by traveling across the interface, similar to Embodiments 1 and 2.

[0071] Furthermore, since the sealing portion 208 is in contact with the lid 203, the semiconductor layer 223, and the base substrate 221, electrical conductivity can be established between the lid 203, the semiconductor layer 223, and the base substrate 221. This allows excess charge accumulated in the semiconductor layer 223 to be released to the lid 203 and the base substrate 221, preventing malfunctions.

[0072] As described above, the inertial sensor 201 of this embodiment provides the following effects in addition to the effects of Embodiments 1 and 2. The inertial sensor 201 of this embodiment further comprises a base substrate 221 as a substrate, an insulating layer 224 as a first insulating layer provided between the base substrate 221 and the cover 203, a semiconductor layer 223 provided between the base substrate 221 and the insulating layer 224, and an embedded insulating layer 222 as a second insulating layer provided between the base substrate 221 and the semiconductor layer 223. The hole 7 includes grooves 233 provided in the insulating layer 224, the semiconductor layer 223, and the embedded insulating layer 222, opening toward the cover 203, and the sealing portion 208 is in contact with the base substrate 221. According to this configuration, the hole 7 includes grooves 233 provided in the insulating layer 224, semiconductor layer 223, and embedded insulating layer 222 of the substrate 202, and the sealing portion 208 fills the grooves 233 and is in contact with the base substrate 221, so a good contact surface can be formed between the sealing portion 208, the insulating layer 224, the semiconductor layer 223, the embedded insulating layer 222, and the base substrate 221.

[0073] In this embodiment, the inertial sensor 201 is further electrically connected to the cover 203, the semiconductor layer 223, and the base substrate 221 via a sealing portion 208. With this configuration, there is no need to provide separate wiring to connect the lid 203, the semiconductor layer 223, and the base substrate 221, thus reducing the number of components, the number of processes, and costs, while also improving reliability.

[0074] 4. Embodiment 4 4.1. Overview of Inertial Measuring Devices Figure 11 is an exploded perspective view showing an inertial measurement device according to this embodiment. Figure 12 is a perspective view of a substrate having an inertial sensor mounted on the inertial measurement device shown in Figure 11. The Inertial Measurement Unit (IMU) 2000 is an inertial measurement device that detects the attitude and behavior of mounted devices such as automobiles and robots. The IMU functions as a 6-axis motion sensor equipped with a 3-axis accelerometer and a 3-axis angular velocity sensor.

[0075] The inertial measuring device 2000 is a rectangular prism with a roughly square shape in plan view. Screw holes 2110 are formed near two vertices located diagonally across the square, serving as fixing points. The inertial measuring device 2000 can be fixed to the mounting surface of an object such as an automobile by passing two screws through these two screw holes 2110. Furthermore, by selecting components and modifying the design, it is possible to miniaturize the device to a size suitable for mounting on, for example, a smartphone or digital camera.

[0076] The inertial measurement device 2000 comprises an outer case 2100, a connecting member 2200, and a sensor module 2300. The sensor module 2300 is inserted into the outer case 2100 with the connecting member 2200 interposed between them. The outer case 2100 has the same external shape as the overall shape of the inertial measurement device 2000 described above, with a roughly square rectangular parallelepiped in plan view, and screw holes 2110 are formed near two vertices located along the diagonal of the square. The outer case 2100 is box-shaped, and the sensor module 2300 is housed inside it.

[0077] The sensor module 2300 comprises an inner case 2310 and a circuit board 2320. The inner case 2310 is a support for the circuit board 2320 and is shaped to fit inside the outer case 2100. The inner case 2310 also has a recess 2311 to prevent contact with the circuit board 2320 and an opening 2312 to expose a connector 2330, which will be described later. The inner case 2310 is joined to the outer case 2100 by a joining member 2200. The circuit board 2320 is also joined to the lower surface of the inner case 2310 by adhesive.

[0078] As shown in Figure 12, the top surface of the substrate 2320 is equipped with a connector 2330, an angular velocity sensor 2340z for detecting angular velocity around the Z axis, and an acceleration sensor 2350 for detecting acceleration in the X, Y, and Z axes. Additionally, the sides of the substrate 2320 are equipped with an angular velocity sensor 2340x for detecting angular velocity around the X axis and an angular velocity sensor 2340y for detecting angular velocity around the Y axis. The inertial sensor 1 of this embodiment can be used as the acceleration sensor 2350.

[0079] Furthermore, a control IC 2360, which functions as a control circuit, is mounted on the underside of the circuit board 2320. The control IC 2360 is an MCU (Micro Controller Unit) that controls various parts of the inertial measurement device 2000. The memory unit stores programs that define the order and content for detecting acceleration and angular velocity, programs that digitize the detected data and incorporate it into packet data, and other associated data. In addition, several other electronic components are mounted on the circuit board 2320.

[0080] As described above, the inertial measuring device 2000 of this embodiment provides the following effects in addition to the effects of embodiments 1 to 3. The inertial measuring device 2000 of this embodiment comprises the inertial sensor 1 described above and a control IC 2360 as a control circuit for controlling the driving of the inertial sensor 1. This configuration makes it possible to provide an excellent inertial measurement device 2000 that can maintain reliability over a long period of time. [Explanation of Symbols]

[0081] 1...Inertial sensor, 2...Substrate, 21...Base substrate, 21a...Top surface, 21b...Recess, 22...Embedded insulating layer, 23...Semiconductor layer, 24...Insulating layer, 24a...Insulating layer, 24b...Insulating layer, 3...Lid, 3a...Bottom surface, 3b...Top surface, 31...Recess, 32...Processed part, 33...Groove, 4...Functional element, 5...External connection terminal, 51...Wiring layer, 6...Adhesive layer, 6a...First adhesive layer, 6b...First 2 Adhesive layer, 7... Hole, 8... Sealing part, 8a... First part, 8b... Second part, 10... Package, 101... Inertial sensor, 102... Base, 102a... Top surface, 103... Lid, 106... Contact Adhering layer, 106a...first adhesive layer, 106b...second adhesive layer, 108...sealing part, 108a...first part, 108b...second part, 108c...third part, 108d...fourth part, 121...base Substrate, 123...semiconductor layer, 124...insulating layer, 124a...insulating layer, 124b...insulating layer, 132...processed part, 133...groove, 201...inertial sensor, 202...base, 203...lid, 206...adhesive layer, 206a...first adhesive layer, 206b...second adhesive layer, 208...sealing part, 208a...first part, 208b...second part, 208c...third part, 208d...fourth part, 208e... Part 5, 208f... Part 6, 221... Base substrate, 222... Embedded insulating layer, 223... Semiconductor layer, 224... Insulating layer, 232... Processed part, 233... Groove, 2000... Inertial measurement device, 2340x... Angular velocity sensor, 2340y... Angular velocity sensor, 2340z... Angular velocity sensor, 2350... Acceleration sensor, 2360... Control IC, Peripheral area... P.

Claims

1. Substrate and, A lid that forms a space between itself and the substrate, A capacitive element made of a semiconductor layer is arranged in the aforementioned space, An adhesive layer is provided in the peripheral region surrounding the aforementioned space, which adheres the substrate and the lid together. The surrounding region includes a sealing portion that seals the hole between the space and the outside, The sealing portion is provided in contact with the lid and the base, and includes the material of the lid and the material of the adhesive layer. Inertial sensor.

2. The base comprises a substrate and a first insulating layer provided between the substrate and the lid, and the hole includes a groove provided in the lid and opening toward the base. The sealing portion is in contact with the first insulating layer. The inertial sensor according to claim 1.

3. The substrate comprises a substrate, a first insulating layer provided between the substrate and the cover, and the semiconductor layer provided between the substrate and the first insulating layer. The hole is provided in the first insulating layer and includes a groove that opens toward the lid. The sealing portion is in contact with the semiconductor layer. The inertial sensor according to claim 1.

4. The cover and the semiconductor layer are electrically connected via the sealing portion. The inertial sensor according to claim 3.

5. The substrate comprises a substrate, a first insulating layer provided between the substrate and the cover, a semiconductor layer provided between the substrate and the first insulating layer, and a second insulating layer provided between the substrate and the semiconductor layer. The holes are provided in the first insulating layer, the semiconductor layer, and the second insulating layer, and include grooves that open toward the lid. The sealing portion is in contact with the substrate. The inertial sensor according to claim 1.

6. The cover, the semiconductor layer, and the substrate are electrically connected via the sealing portion. The inertial sensor according to claim 5.

7. The lid has a processed portion having a recess in a position that overlaps with the sealing portion when viewed from above. An inertial sensor according to any one of claims 1 to 6.

8. An inertial sensor according to any one of claims 1 to 7, The system includes a control circuit for controlling the drive of the inertial sensor. Inertial measuring device.

9. A method for manufacturing an inertial sensor comprising a substrate, a lid that forms a space between itself and the substrate, and a capacitive element made of a semiconductor layer disposed in the space, The process of forming a groove on the first surface of the lid that connects the space and the outside, The first surface of the lid is bonded to the base via an adhesive layer to connect the space and the outside, forming a hole consisting of the groove and the base, The process includes the step of irradiating the hole with laser light from a second surface opposite to the first surface of the lid, thereby forming a sealing portion that seals the hole with the molten material of the lid, A method for manufacturing an inertial sensor.

10. A method for manufacturing an inertial sensor comprising a substrate, a lid that forms a space between itself and the substrate, and a capacitive element made of a semiconductor layer disposed in the space, The process of forming a groove on the third surface of the substrate that connects the space and the outside, The steps include: adhering the lid to the third surface of the base via an adhesive layer to connect the space and the outside, and forming a hole consisting of the groove and the lid; The process includes a step of irradiating the hole with laser light from the lid side to form a sealing portion that seals the hole with the molten material of the lid, A method for manufacturing an inertial sensor.

11. The process includes forming a processed portion having a recess at a position overlapping with the groove of the cover, In the step of forming the sealing portion, the laser light is irradiated onto the processing portion to form a first sealing portion made of the lid material and a second sealing portion made of the lid material and the adhesive layer material. A method for manufacturing an inertial sensor according to claim 9 or claim 10.

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